Electrolytic condenser and method of making same



March 25, 1941. J. B. BRENNAN 2,235,823

ELECTROLYTIC CONDENSER'AND METHOD OF MAKING SAME v Original Filed Dec. 2, 1935 Z'mnentor JOSAPHB BEEN/VAN attorneys Patented Mar. 25, 1941 UNITED STATES HECTRDLYTIC CONDENSER AND METHOD OF MAKING SAME Joseph B. Brennan, Euclid, Ohio Application December 2, 1935, Serial No. 52,502

, Renewed December 11, 1939 4 Claims.

This invention relates to electrolytic condensers and methods of making same, and more particularly to the construction of electrolytic condensers or rectifiers of the type embodying a liq- 5 uid electrolyte and a filmed anode. Condensers of this type find a wide use in radio receivers, and for such use the condensers must be compact and neat appearing and should be provided with means for conveniently mounting the condensers in the chassis of the receiver. This application is a continuation in part of my copending application Serial No. 662,107, filed 'March 22, 1933, now Patent No. 2,104,018, patented January 4, 1938.

Condensers of this type ordinarily comprise a container of aluminum or other suitable metal which forms the cathode of the condenser and retains the electrolyte, and an anode having a surface of aluminum or other film forming metal supported within the cathode and submerged in the electrolyte. It has been found that thean ode or the terminal therefor are subject to severe corrosion if they extend out ofthe electrolyte. To overcome this difficulty, it has been a common practice to arrange the condensers so that the lead or terminal for the anode projects out through the bottom of the cathode container, and thus the entire anode and the lead therefor are submerged in the electrolyte.

It is among the objects of my invention to provide a condenser of the type described above which can be manufactured economically and which will be durable andgive trouble free ser-' vice. Another object of my invention isto provide an electrolytic condenser in which the containers may be made economically from metallic tubing. Another object is to provide a rapid and economical method. of making condensers in which the containers are formed of metallic tubing. A further object is to provide a closure for the containers for the electrolyte of condensers which closure can be adapted to form a support for the condenser in an apertured plate. Another object of my invention is the provision of condensers which may be mounted by means of spring clips without requiring the use of nuts or other threaded members. Another object is the provision of anodes for condensers which are compact and which will have a large capacity for the volume occupied by the anodes.

Further objects and advantages of my invention will become apparent from the following description of preferred forms thereof, reference 55 being made to the accompanying drawing, in

which Fig. 1 is a vertical section of a preferred form of my condenser; Fig. 2 is a transverse section through the condenser shown in Fig. 1 as indicated by the line 2-2 of F18. 1: Fls. 3 is a plan view of the condenser of Fig. 1, diagrammatically illustrating one step in the assembly of the condenser; and Fig. 4 is a perspective view of a securing .clip which I preferably emplo for mounting the condensers.

As shown in Figs. 1 and 2, a preferred form of my condenser may comprise a substantially cylindrical container l which acts as the oathode of the condenser and which is preferably formed by cutting a section of aluminum tubing of the proper diameter to the desired length. The container forms a reservoir for the electrolyte, and an anode II is disposed within the container l0 and is provided with a riser or terminal I! which serves to conduct electricity to the anode. The container is preferably filled with electrolyte to a level above the upper end of the anode I I.

To provide an anode which can be produced economically and which will have a high capacity as compared with the volume of space whichit occupies, I preferably form the anode by molding a base or core of porcelain, Bakelite, or other suitable insulatin material into the form shown and having a cylindrical base portion l3 and an upwardly extending portion l5 provided with a plurality of radially extending ridges 0r fins l6 and a central opening or passageway ll which is adapted to receive the riser 12. The base or core of insulating material is formed into a completed anode preferably by depositing a porous, conductive coating of aluminum thereon by spraying the aluminum in a finely divided molten condition, as described in my copending application Serial No. 662,107, filed March 22, 1933, now Patent No. 2,104,018. As described in that application, the spraying operation produces a porous conductive surface havinga great superficial area which is provided with a coextensive dielectric film in the subsequent film-forming operation, thus producing a very large effective surface area on the anode.

I o make an electrical connection between the deposited metal on the surface of the form or core, the riser l2 preferably extends through the entire length of the core and is provided with an enlarged head riveted over as indicated at 19. The riser is assembled in this manner before the spraying operation takes place, so that the sprayed coating overlying the enlarged head of the riser will make an efiective contact between the active surface of theanode and the riser.

By extending the riser through the entire length of the porcelain form, as shown, I obtain container, so that there is very low hydrostatic pressure of electrolytetending to cause the electrolyte to flow along the riser to the exterior of the condenser. To assist further in preventing leakage, I may coat the shank of the riser that extends through the porcelain anode base with a suitable porcelain cement before inserting the a strong mechanical joint between the closure member and the container.

This inward deformation as at 2% functions highly to compress the sealing material 28 to in= sure a strong and leakproof connection. As indicated diagrammatically in Fig. 3, this deformation is preferably carried out by a rolling operation, a series of three rolls 25 being employed,

and the rolls being moved inwardly toward the axis of the condenser as they are rolled around the outer surface of the container l0, but those skilled in the art will appreciate that if desired the groove 24 may be formed by other methods, such as by a spinning operation, rather than by rolling.

After the anode has been secured in place as described above, the tube may be filled with electrolyte, preferably to a level above the top of the anode II, and thereafter the upper end of the tube may be closed as by any suitable cap 26 preferably provided with a vent of any ordinary construction.

In order to support the condenser in an apertured plate such as thatshown at 21 and to provide a means whereby the condenser may be secured in position rapidly and quickly, the anode base is provided with a downwardly projecting stud-28 provided with parallel slots 29. These slots are disposed immediately beneath the lower surface of the plate 21 and are adapted to receive the legs of the resilient securing clip 30. This clip, which is illustrated in Fig. 4 of the drawings, is preferably made in accordance with the teachings of the Baldwin Patent No. 1,875,209 and preferably is provided with down turned points 30 which are adapted to gouge into the supporting plate 21 in such a manner as to prevent the clip from being backed away from the stud 28, and to prevent the clip from being robated with respect to the plate 21.

By the use of a clip of this type, rotation of the condenser with respect to the plate is prevented because the condenser is held from rotation with respect to the clip by engagement of the straight walled slots 29 with the inner surfaces of the legs of the clip. By this construction, my condensers can be mounted rapidly on a supporting plate in a radio instrument or in any other device with which they may be used. In some instances, it may be desirable to insulate boththe anode and cathode of the condenser from the support for the condenser. This can be accomplished readily by insulating the container I 0 from the plate 21 by an insulating 1 washer 32-.

From the foregoing description of a preferred form of my invention, it will be seen that I have provided a durable and efilcient condenser which The operations employed to form a seal between the anode and the container may be carriedlout rapidly and at low cost while my condensers can be manufactured economically from sections of aluminum tubing. It will be evident to those skilled in the art that various modifications in my invention can be made without departing from the spirit thereof. It is therefore to be understood that my invention is not limited to the various forms illustrated or described herein or in any manner other than by the scope of the appended claims.-

I claim:

1. An electrolytic condenser comprising, in combination, a tubular container adapted to form the cathode of the condenser, an anode disposed within said container and comprising a porcelain form having a layer of film forming material deposited thereon, said form having a base portion constituting a closure for the tubular container, a gasket of sealin material disposed between said base portion and said tubular container, said tubular container being deformed inwardly to compress said sealing material, and a riser extending through said base portion and said porcelain form from the exterior of the condenser and into contact with the film forming v material on the surface of said porcelain form.

2. An electrolytic device comprising, in combination, a tubular container for electrolyte, an electrode disposed within said container and comprising a porcelain form having a conductive metallic layer deposited thereon, said form having a base portion constituting a closure for the tubular'container, and a gasket of sealing material disposed between said base portion and said tubular container, said tubular container being deformed inwardly to compress said sealing ma terial.

3. An anode for an electrolytic condenser comprising a base of insulating material provided with radially extending fins, the surfaces of said insulating material having deposited thereon a conductive layer of finely divided film forming material and having a dielectric film formed on the surface of said film forming material and conforming in contour thereto, and a riser or terminal extending through said base of insulating material and making an electrical connection with said layer of film forming material at one end thereof.

4. An electrolytic device comprising, in com bination, a container for electrolyte,- an electrode disposed within said container comprising a form composed of insulating material having a conductive metallic layer deposited thereon, said-form having a portion constituting a closure for said container, and means for creating a seal between said portion of said form and said container.

' JOSEPH B. BRENNAN. 

